There’s probably several terms it could come under - intrusive thoughts, black and white thinking. Ultimately an emotional regulation problem.
It might be that when you were little, you were shamed or judged for showing certain feelings like anger, so you learn to not express them or cover them up. Very likely, as you’ve said, “This is stupid; I've done it all my life… mental behaviour”, and “really stupid habit” - where did you pick up the idea that it’s stupid or ‘mental’ to feel angry? And you’ve described the feelings as “childish” - it could be that they’re a young expression of feelings that were never seen or acknowledged by your parents when you were little, so you might be kind of stuck in that childish way of feeling as you’ve never had help from a regulated adult to help you develop a more mature, regulated way of feeling and expressing anger.
Not expressing feelings can lead to them coming out as an explosion or at a tangent or as intrusive thoughts, so that might explain the sort of extreme thoughts. Covering them up can lead to you developing a sort of mask or social front which means you show the bits of yourself that were acceptable in your childhood (e.g. likely it was safe and acceptable to feel happy, content, calm, so you might feel those are acceptable feelings to show to others while you hide the more difficult feelings like anger, frustration, disgust).
on the suicidal thoughts... When you feel like your emotions are too big to cope with, it can feel like the only way to escape the feelings is to get out of your nervous system i.e. die. When you have the right support with acknowledging and feeling your feelings (a therapist is ideal), you can learn that feeling and expressing your emotions is possible and doesn’t kill you, and you might find the suicidal thoughts fade.
All of this stuff are normal adaptations to growing up in emotionally stunted environment or without enough emotional support. There’s nothing mental or wrong with you.
If any of that resonates and you want to know more, Complex PTSD by Pete Walker is a good book to give an introduction and overview to why this stuff happens. He calls suicidal thoughts and emotional overwhelm “emotional flashbacks”, and he has his steps to managing these in his book and on his website. Therapy and mindfulness meditation can also help you improve your emotional awareness and regulation.